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Biomedical subjects

J R Hansell

Publications and source records attributed to J R Hansell.

18 recordsLinked to original sources
PubMed1989

Effect of therapeutic digoxin antibodies on digoxin assays.

The introduction of therapeutic digoxin antibodies in the treatment of digoxin toxicity has resulted in spurious results in the many assays of cardioglycoside in serum of patients receiving this therapy. An evaluation of currently used assay methods was incorporated into a pilot Ligand Assay Survey Program of the College of American Pathologists to define which assays were unaltered by the presence of a therapeutic digoxin antibody (Digibind). Disparity of affinity constants of the therapeutic and kit antibodies is the most likely explanation for erroneous values. Specific methods are defined that appear to be free of this phenomenon.

Digoxin↗
PubMed1988

The use of quantitative perfusion fluorometry to measure relative tumor and liver blood flow after transient microembolization.

Optimal chemotherapy delivery to the tumor depends on regional drug concentration, tumor perfusion, tissue drug uptake, and metabolism. Modulation of tumor blood flow has been used to improve tumor response to treatment. Transient microembolization is one method to alter regional blood flow, but its effects on relative changes in tumor and liver blood flow have not been previously measured. This study used quantitative perfusion fluorometry (QPF) to evaluate blood flow distribution in liver and tumor before and after hepatic arterial infusion of degradable starch microspheres (DSMs) in 10 New Zealand white rabbits. QPF was compared with radioactive xenon-133 washout, an established method for measuring blood flow. Xenon-133 was injected intraparenchymally and the clearance rate was measured allowing calculation of relative blood flow. QPF was then used to measure liver and tumor blood flow in a hepatic VX-2 tumor model after hepatic artery injection of DSMs. Initial tumor blood flow was 55% of liver flow. DSMs produced a significant and transient decrease in hepatic blood flow that was decreased to 40% of baseline after 25 min. Changes in relative hepatic blood flow after DSMs as measured by QPF correlated strongly with results obtained by xenon-133 washout (R = 0.97, P less than 0.01). Fluorometry's simplicity and reliability may be clinically useful to evaluate tumor blood flow characteristics.

Animals↗
PubMed1986

Paget's disease of bone in patients with gout.

In a study designed to evaluate the radionuclide images in patients with gout, six (23%) of the 26 patients had clear evidence of Paget's disease of bone by technetium Tc 99m medronate imaging. A reference population consisting of 333 technetium Tc 99m medronate bone scans ordered for other reasons was reviewed, and only seven scans (2.1%) were found to have evidence of Paget's disease. This difference was found to be highly significant. All cases of Paget's disease were confirmed by independent radiologic evaluation. We conclude that there is a significant association between Paget's disease and gout, the basis for which is not yet known.

Aged↗
PubMed1979

Laboratory intercomparison of commerical digoxin kits.

Results of recovery, precision, and effect of a protein deficient matrix on commercial digoxin assay kits is reviewed for pools distributed in 1978 by the Basic Ligand Assay Survey Program of College of American Pathologists. Variability among kits is present in terms of all three areas studied. Nevertheless, commonly used methods by participants have recovery rates approaching 100%; coefficients of variation are less than 10% at therapeutic serum levels.

Digoxin↗
PubMed1979

Effect of water and fat on gastric emptying of solid meals.

Gastric emptying of solid egg meals tagged with 99mtechnetium sulfur colloid was studied in 10 normal subjects and in 6 patients after truncal vagotomy, antrectomy, and gastrojejunostomy (Billroth II) for peptic ulcer disease. Technetium sulfur colloid was found to bind more firmly to cooked egg whites than did the water soluble marker DTPA. Water accelerated gastric emptying in Billroth II patients to a greater degree than in normal subjects, in whom the effect of water was minimal and transient. Fat inhibited solid emptying both in normals and in Billroth II patients. These findings suggest that in humans there are jejunal receptors for fat that may inhibit gastric emptying even following truncal vagotomy.

Eating↗
PubMed1978

Reproducibility of mean values of duplicate specimens in the Basic Ligand Assay Survey.

Three paired samples were distributed at three--six-month intervals in the Basic Ligand Survey during 1976. The stabilities of mean values obtained by widely used commercial kit procedures and by all methods for eight analytes are reported. Significant improvements in accuracy and long-term precision were identified in assays for digoxin and thyroxine during 1976. However, a number of assays yielded unstable mean values that affected both within--laboratory maintenance of quality control and medical usefulness of the results.

Digoxin↗
PubMed1976

Reliability of chemical tests for fecal occult blood in hospitalized patients.

In 39 hospitalized patients with suspected gastrointestinal bleeding and given intravenous 51Cr-labeled red cells, reactions of three chemical spot tests for fecal occult blood were compared with the "true" blood loss as determined by stool radioassay. Guaiac reagent and orthotolidine (Hematest) tablets were extremely sensitive, but yielded false-positive reaction rates of 72% and 76%, respectively on the 240 stool specimens compared. A modified guaiac test (Hemoccult) exhibited a false positive rate of 12%. Of the 27 patients entering the study due to positive guaiac or Hematest screening tests, 17 (63%) were not bleeding. Hemoccult, approximately 1/4 as sensitive as guaiac and Hematest, could miss lesions with low rates of bleeding unless multiple stools were tested. While barium had no effect, iron therapy or laxatives tended to lower both false-positive and false-negative reactions for all reagents. A positive Hemoccult test usually indicated significant gastrointestinal bleeding and would appear to be the test of choice provided at least 3 stools are tested to minimize false-negative results.

Barium Sulfate↗
PubMed1976

Regional bronchoconstriction in asthma. 133Xenon washout scans following parenteral methacholine.

To determine the influence of bronchoconstriction on the distribution of ventilation during an asthma attack, pulmonary clearance of 133xenon was evaluated in four normal and eight asthmatic subjects within three to five minutes after intramuscular injection of methacholine. In asthmatics, administration of 4-10 mg methacholine resulted in a decrease of forced vital capacity of 28.5 +/- 5.1 (SE) percent and a decrease in expiratory flow at 60 percent vital capacity of 44.2 +/- 6.9 percent (P less than 0.001). The cumulative ventilation required to reach 50 percent of the pre-washout radioactivity increased from 3.6 +/- 0.8 to 9.9 +/- 1.6 L after administration of the drug (P less than 0.05). The normal subjects showed no ventilatory effects after receiving 10 mg methacholine. Comparison of clearance of 133xenon from ten areas of lung (each representing approximately 6 percent of the surface area of one lung) showed that all areas were affected to approximately the same extent during drug-induced asthma. These findings suggest that parenteral methacholine is an effective way to demonstrate airway hyperreactivity and that the airway response to methacholine in asthmatics is relatively generalized throughout the lung.

Adult↗
PubMed1976

Three-years' experience in interlaboratory testing of commercial digoxin kits.

Results of digoxin assays obtained from participants in Survey Programs of the College of American Pathologists over a span of three years are reviewed according to recovery rates and clinical interpretation of results obtained. Discrepancies in recovery rates by kits employing iodinated and tritiated antigens were observed in 1972 and 1973. More uniform recovery rates were observed in 1974. Clinical interpretation of the results obtained by participating laboratories was affected by the methods used during the first two years and by the apparent failure of individual laboratories to establish their own therapeutic ranges.

Digoxin↗
PubMedDate not supplied

The effects on synovial permeability and synovial fluid leukocyte counts in symptomatic osteoarthritis after intraarticular corticosteroid administration.

The mode of action of intraarticularly administered corticosteroids was studied. Fifteen patients with osteoarthritis and painful effusions had one knee injected with normal saline, triamcinolone hexacetonide 20 mg or prednisolone tebuate 20 mg. Fifteen millicuries of 99mTc-labeled albumin was given intravenously before and at various time intervals after the injection of the depot corticosteroid or saline. Whole blood and synovial fluid (SF) samples were used for blood to SF count rate ratio determinations. SF white blood cell counts (WBC) were also performed. The results indicated that intraarticular depot corticosteroids decreased synovial permeability and caused increases in the SF WBC. Moreover, decreases in pain and knee swelling correlated better with a decrease in vascular permeability, as assessed by the count ratio, than with SF leukocytosis.

Adrenal Cortex Hormones↗